Digital-to-analog converters (DACs) find application in a variety of different electronic applications. Typically, DACs have inherent non-linearity and distortions that cause spurious harmonics at the output of the analog waveform. In some applications, it is important that the conversion from the digital domain to the analog be highly accurate. For example, signal analysis instruments and signal waveform output systems need to produce highly accurate analog excitation signals from corresponding digital signal data. In most such applications, conversion errors referred to as distortion are a function of the input digital data and the non-linearity of the DAC are much more important than errors that are uncorrelated, referred to as noise. The noise portion of any conversion error can be reduced by averaging the waveform over time. The distortion portion of the error, however, cannot.
To achieve low distortion digital-to-analog conversion, high precision DACs have been fabricated with finely matched components. An alternative approach is to quantify the distortion error of a particular converter at all possible input signal conditions and then to implement a correction circuit that compensates for the circuit's known error. These approaches, however, are expensive and unsuitable for large volume production.